Internal solitary waves (ISWs) in the northern South China Sea are the most energetic in the world’s oceans. It is widely accepted that these ISWs are generally originate from the Luzon Strait. They usually have a regular occurrence, phase-locked to tidal forcing in the Luzon Strait. However, we present field measurements showing irregular occurrence of ISWs on the northern shelf of the SCS. This irregular occurrence is in striking contrast to the prominent predictability of ISWs originated from LS. We reveal that the intermittent nature is due to the local generation of ISWs on the shelf. The coupling of different flow components plays a significant role in ISW generation on the shelf. Based on the updated knowledge, by combining new observations, numerical simulations, theoretical and diagnostic analyses, we aim to clarify the process, dynamical mechanism and influence key factors of the joint effects of tidal and shelf flows on the local generation of ISWs. Additionally, we aim to point out the key parameters controlling the local generation of ISWs, and reveal the spatial and temporal distribution features of local generated ISWs on the continental shelf of the SCS by the typical shelf flows. The outcomes of this research are in order to improve the knowledge and forecasting capability of the generation and propagation of ISWs on the continental shelf.

internal solitary waves, local generation, joint effects of tidal and shelf flows, continental shelf, South China Sea